Motorized karts, also sometimes known as go-karts, are a popular type of motor sport. Motorized karts come in an astonishing range of complexity and power. Simple four-stroke go-karts are available, as are powerful two-stroke engine karts. Some motorized karts make use of alternative power supplies, including alcohol fuel, electric motors, and propane engines. Motorized karts can range in power from 15 horsepower all the way up to 90 horsepower and above. Motorized go-karts are often used in racing. Go-karts are adaptable enough to be used on a large number of surfaces, and a number of custom tracks for karting also exist.